CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Millions	Total	Common stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2018		100
Beginning Balance at Dec. 31, 2018	$ 6,298	$ 0	$ 4,341	$ 1,983	$ (26)
Increase (Decrease) in Stockholder's Equity
Net income	578			578
Total other comprehensive income (loss)	(1)				(1)
Common dividends declared to parent	(478)			(478)
Contribution of capital by parent	599		599
Balance (in shares) at Dec. 31, 2019		100
Ending Balance at Dec. 31, 2019	6,996	$ 0	4,940	2,083	(27)
Increase (Decrease) in Stockholder's Equity
Net income	588			588
Total other comprehensive income (loss)	3				3
Common dividends declared to parent	(824)			(824)
Contribution of capital by parent	$ 830		830
Balance (in shares) at Dec. 31, 2020	100	100
Ending Balance at Dec. 31, 2020	$ 7,592	$ 0	5,770	1,846	(24)
Increase (Decrease) in Stockholder's Equity
Net income	660			660
Total other comprehensive income (loss)	2				2
Common dividends declared to parent	(466)			(466)
Contribution of capital by parent	$ 656		656
Balance (in shares) at Dec. 31, 2021	100	100
Ending Balance at Dec. 31, 2021	$ 8,444	$ 0	$ 6,426	2,040	$ (22)
Increase (Decrease) in Stockholder's Equity
Adoption of ASC Topic 326	$ (1)			$ (1)